Q: Nutrition labels list the “% Daily Value” for vitamins and minerals. How does that differ from the old recommended dietary allowances (RDAs)?
A: The Food and Drug Administration (FDA) created Daily Values for the labeling of vitamins and minerals on foods and supplements. They are based on the RDAs, which were set by the Institute of Medicine back in 1941 and have been periodically revised.
Food labels must list the “% Daily Value” (or %DV) for calcium, iron, vitamin A and vitamin C in a standard serving; other nutrients are optional. Thus, if a cup of yogurt says 40% DV for calcium, that means it has 400 milligrams (mg), or 40 percent of the Daily Value for calcium, which is 1,000 mg.
While most RDAs vary by age and sex, the Daily Value is a single number, simplified for use on labels. Keep in mind that not all Daily Values reflect current government recommendations. For example, in 2000 the RDA for vitamin C was raised to 75 mg for women and 90 mg for men, but the Daily Value remains 60 mg. And the Daily Value for vitamin D is still 400 IU, while three years ago the RDA was raised to 600 IU through age 70, and 800 IU for those over 70. Still, the “% DV” gives you a ballpark idea of what you’re getting.